1. Field of the Invention
The present invention relates to an electric junction box that is connected to a wire harness for an automobile, and more particularly, relates to an electric junction box including a plurality of stacked and connected electric junction boxes.
2. Description of Background Information
The number of circuits that are housed inside a junction box or electric connecting box have sharply increased in recent years in accordance with a sharp increase in the electric equipment and the number of components that are mounted on an automobile. The number of parts required for forming high density branched circuits has sharply increased, and the assembly process is more complex and difficult.
As an example of such a type of junction box, a conventional junction box is illustrated in FIGS. 7A and 7B. The conventional junction box houses internal circuits in which bus bars 3, forming circuits by stamping an electroconductive material, and insulation boards 2 are alternately stacked inside the junction box. The junction box includes an upper case 1 and a lower case 4. A connector housing portion 1a, a fuse housing portion 1b, a relay housing portion, and the like are provided on the upper face of the upper case 1. An external circuit is electrically connected to the bus bars 3 by fitting the connector 5 at the end of a wire harness W/H in the connector housing portion 1a. 
However, since the fuse and relay are installed only on the upper face of the upper case 1 in the conventional junction box, installation space is limited, and there is the problem that an increase in the number of fuses and relays cannot be accommodated. To overcome this problem, the area in the horizontal direction of the junction box may be enlarged, or the housings for the fuses and relays may be provided on the lower face as well as the upper face of the junction box to enlarge the installation space for the components. However, it is difficult to enlarge the horizontal area of the junction box because the space available for the junction box in an automobile is often limited in the horizontal direction. Further, providing housings for the fuses and relays on both the upper and lower faces of the junction box requires assembly and maintenance in both sides of the junction box, so that maintenance may be performed only by overturning the junction box, making maintenance difficult and problematic.
The present invention was developed to solve the above and other problems. An object of the present invention is to avoid an increase in the size of the junction box, to ease and simplify maintenance, and to provide a large installation area for the components.
In order to solve the above described problems, an electric junction box is provided including a plurality of boxes detachably connectable in vertically stacked layers, and housing portions in which a fuse and/or a relay is connectedly inserted on one face of at least two or more junction boxes, such that the faces provided with fuses and/or relays of the stacked boxes all point in the same direction, such as either an upper or a lower direction, and the housing portions of the fuse and/or the relay are positioned between one face of a box and an adjacently stacked box.
When this construction is provided, since the housing portions are on one side of a box and face in the same direction, a worker can carry out the installation and removal of a fuse and/or relay from one side, and maintenance is improved and made convenient.
For example, when the above described electric junction box is mounted on a vehicle, relay and fuse housing portions of the stacked boxes are positioned facing the opening portion for maintenance of a vehicle, so that the housing portions always face the opening portion upon removal of the outermost box. Therefore, convenience and access is remarkably improved because it is not necessary to turn the box over and remove it from the vehicle.
Further, since the fuse and relay housing portions are provided on only one face of at least two or more of boxes, the number of components can be greatly increased without increasing the horizontal space required by the electric junction box in a vehicle.
Further, since the above described electric junction box is divided into a plurality of boxes, a flexible circuit design is possible. For example, even if variation of a circuit is required, it may be changed without changing the entire electric junction box by providing a box which houses a basic circuit having less variation and a box which houses a circuit (or an optional circuit) in which a variation is anticipated. Further, a box housing a circuit may be divided depending on the location of a circuit load, and the like. Therefore various designs become possible.
The above described stacked boxes may include any suitable number of boxes, such as for example, two to ten boxes, the locking portion and the catch portion are provided on an outer face of the respective boxes, and the locking portion and the catch portion of the adjacent boxes are detachably locked. Therefore assembly is easily performed with one touch, and removal at maintenance can be easily performed.
The above described stacked boxes are provided with an internal circuit consisting of any suitable components, such as, for example, bus bars, a single core wire, a flat harness and/or a printed circuit board inside a case including a lower case and an upper case, and the internal circuitry of the stacked boxes is electrically connected through an internal circuit-connecting portion provided on the opposing faces of adjacent boxes.
Since the internal circuit-connecting portions between the respective boxes are provided at the opposing faces of the respective boxes, the connecting portions are covered after stacking the respective boxes, therefore safety, treatment, appearance and the like are improved in comparison with connecting by electric wires or the like at the outer faces of the electric junction boxes.
Further, the conductor in the above described internal circuitry may include any of either bus bars, a single core wire, or a flat cable, or a combination thereof. Further, the internal circuit may include a printed circuit board.
The connector portion may be provided on opposing faces of the adjacent boxes, the connector portion may be fitted, and the terminals of the internal circuit which extend inside are detachably connected. Therefore the electrical connection between the respective boxes can be obtained by one touch at the same time as stacking the respective boxes, and removal thereof can be easily carried out.
Alternatively, in place of the above described connector connection, the relay terminals connected to the internal circuit may extend from opposing faces of adjacent boxes, a recess may be provided on the opposing faces, and the relay terminals may be inserted into the recess and detachably connected to the internal circuit. In this case, it is not required to form a connector housing.
Alternatively, in place of the above described connector connection and relay terminal connection, there may be contact pieces connected to the internal circuit arranged on opposing faces of the adjacent boxes, and the adjacent boxes may be connected by a bolt screwed into the case through a bolt hole, and the internal circuits are connected through the contact pieces at the same time as connecting the boxes.
A connector connected to the wire harness of an external circuit may be provided on the upper faces of the stacked boxes or/and the lower faces or/and the side faces of the respective boxes, and may be provided at a position at which it is easily connected with the connector of the wire harness.
Further, the wire harness of the external circuit may be inserted inside a box without a connector, and the conductor of the internal circuit may include electric wires.
According to an aspect of the present invention, an electric junction box is provided including a plurality of boxes, each of the boxes including an upper face and a lower face, the plurality of boxes being stacked in vertical layers and detachably connectable to each other so that the upper face of one of the boxes is adjacent the lower face of the next adjacent box, and a least one housing portion provided on one face of at least two of the plurality of boxes, the housing portions configured to receive a component; wherein the plurality of boxes are vertically stacked so that all of the components received in the housing portions of the boxes face in one direction and the components are positioned between the upper face of the box in which it is received and the lower face of the next adjacent box. The plurality of boxes may include two to ten boxes.
According to a further aspect of the present invention, The each of the boxes may include an upper case, a lower case, and an internal circuit including one or more bus bars, single core wires, flat harnesses or printed circuit boards inside the case, and wherein the internal circuits of the boxes are electrically connected to each other through an internal circuit connecting portion provided on opposing faces of adjacent boxes. The connector portions may be provided on the cases on opposing faces of the boxes, the connector portions being fitted to each other so that terminals on the internal circuits extending into the connector portions are detachably connected to each other. Further, a relay terminal may extend from a respective case of one of the boxes, and an aperture may be provided in the case of an adjacent box so that the relay terminal is inserted into the aperture and the relay terminal is detachably connected to the internal circuit in the case of the adjacent box.
In a further aspect of the present invention, the electric junction box includes contact pieces connected to an internal circuit on the cases of opposing faces of the adjacent boxes, and the adjacent boxes are connected by a bolt screwed into the case through a bolt hole so that the internal circuits of the adjacent boxes are connected to each other by the contact pieces and the adjacent boxes are connected to each other. The connector connected to a wire harness of an external circuit may be provided at the upper face, the lower face or a side face of the respective boxes. Further, the housing portions may be configured for receipt of a fuse or a relay, and the housing portions may be positioned on an outer face of the stacked boxes so as to face outwardly for maintenance. The electric junction box may further include a locking portion and a catch portion at outer faces of adjacent boxes so that the locking portion and the catch portion of adjacent boxes are detachably locked.